Question: $J$ $K$ $L$ If: $ KL = 6x + 9$, $ JK = 3x + 7$, and $ JL = 70$, Find $KL$.
Solution: From the diagram, we can see that the total length of ${JL}$ is the sum of ${JK}$ and ${KL}$ $ {JK} + {KL} = {JL}$ Substitute in the expressions that were given for each length: $ {3x + 7} + {6x + 9} = {70}$ Combine like terms: $ 9x + 16 = {70}$ Subtract $16$ from both sides: $ 9x = 54$ Divide both sides by $9$ to find $x$ $ x = 6$ Substitute $6$ for $x$ in the expression that was given for $KL$ $ KL = 6({6}) + 9$ Simplify: $ {KL = 36 + 9}$ Simplify to find ${KL}$ : $ {KL = 45}$